1. B. A. Goodman, N. N. Greenwood, and G. E. Turner, Chem. Phys. Lett. 5, 181 (1970).
2. R. J. P. Williams, Quarterly Review 24, 331 (1970).
3. G. W. Dulaney and A. F. Clifford, Mössbauer Effect Methodology 5, 65 (1971).
4. R. Gehrke, Nuclear Data document ANCR-1088, p. 392, gives 21.540 ± 0.006 keV.
5. S. Antman, H. Pettersson, Z. Zehlev, and I. Adam, Z. Physik 237, 285 (1970), gives Eγ = 21.529 ± 0.014 keV and α = 28.5.